The architecture of a pneumatic tire typically includes several layers. By way of example, a tire may include an air impermeable inner liner, a carcass layer, one or more belt cushion layers, and a tread layer. The carcass layer extends between beads located on respective sides of the tire in a manner adjacent to the air impermeable layer. As the tire is pressurized, the carcass layer helps retain the overall shape of the tire by containing the inner air impermeable layer and transferring force to the beads. As the tire is inflated, the beads operate to secure the tire onto the wheel. The carcass layer is typically strengthened by cords constructed from various materials including various steels and/or organic materials such as nylon, rayon, polyester, and the like. One or more belt cushion layers may be located radially outside the carcass layer. The belt cushion layers are typically composed of rubber and are also strengthened by embedded cords. A tread layer is located radially outside the one or more belt cushion layers. The tread layer is generally composed of rubber and contains a plurality of surface features, e.g. peaks and grooves, designed to help the tire grip the road. One or more of these structural features may also be present in a non-pneumatic tire as well, and the present invention is not limited to any particular tire type.
Sometimes it is necessary to remove a section from a tire to make repairs or to replace or install a device onto the tire. For example, the tire may have been damaged by a rupture or tear that extends partly or completely through the tire. In such case, one or more of the structures in the tire architecture as identified above may be damaged. Depending upon the extent and type of damage to the tire (or the nature of the device being added to the tire), it may be necessary to remove a section from the tire. As used herein, “section” means a portion of the tire that includes both the inside and outside surfaces of the tire.
Common tools for removing a section from a tire include air drills, grinders, stones, and wire cutters. The cutting of a tire with a saw blade poses several challenges. For example, while removing a section from the tire, it is generally desirable to avoid damage to cords or other components adjacent to the removed section that will remain with the tire after the section is removed. In addition, control of the saw blade to cut only a predetermined section from the tire can be difficult with a hand tool such as an electric or mechanized jigsaw because of the presence of various durable layers and components in the tire.
Another difficulty in removing a section of the tire with a saw blade is that the cords can only be cut with a jigsaw having a hard blade operated at high speed. In this case, the friction between the saw blade and the rubber causes the rubber to temporarily revert to liquid form, creating an undesirable surface texture surrounding the opening left by the removed section of the tire. A typical jig saw blade “cuts” the cords by pulling the cords until the tension causes them to break. As such, it is difficult to control the physical location where the cords embedded in the various layers of the tire will break. The cords may break on the side of the saw blade adjacent to the sidewall of the tire or the cords may break on the side of the saw blade adjacent to the section of the tire being removed. The cords that break on the side of the saw blade adjacent to the sidewall of the tire typically protrude unevenly from the surface surrounding the removed section of the tire.
Thus, a need exists for a method and system for removing a section of tire that facilitates removal of the section without undesirable damage to the tire and that also provides a better surface texture surrounding the removed section of the tire.